As society becomes increasingly mobile, mobile computing devices are enjoying a tidal wave of popularity and growth. Cell phones, wireless PDAs, wireless laptops and other mobile communication devices are making impressive inroads with mainstream customers. Constraining this growth and limiting customer satisfaction, however, is the lack of a truly adequate high-coverage-area, inexpensive, small, battery-efficient wireless communication system. Cellular data-transmit telephony-based solutions are far from power-efficient, and impose (relative) cost and size burdens that make them unusable. Likewise, other attempts to solve these problems have proved equally unsuitable. For instance, a few entities have attempted to make use of mobile devices that receive information over Frequency Modulated (FM) subcarriers. FM subcarriers (also known as “SCA” for Subsidiary Communications Authorization) utilize the available frequencies above FM stereo within the available modulation bandwidth of an FM station. Subcarriers are typically leased by radio stations, subject to FCC or other national regulation.
Some examples of FM subcarrier systems include the QUOTREK system owned and maintained by the Data Broadcast Corporation (DBC) to deliver stock price quotes to a handheld mobile device. However, the QUOTREK system is a single purpose system limited to receiving stock quotes. The system has various other limitations that make it unusable as a mobile computing device. Likewise, the Seiko Corporation implemented an FM subcarrier system wherein short messages were transmitted to a wrist-worn device. However, the hardware and communications scheme used were relatively primitive, resulting in a need for excessive redundancy in message transmission. These and other shortcomings rendered the Seiko system less than acceptable. Similarly, certain paging systems are based on FM subcarrier use, such as the Radio Data System (RDS) or Mobile Broadcasting System (MBS) systems. However, those systems involve short messages transmitted in a broadcast fashion with limited data rates. Unfortunately, an acceptable mobile device solution has eluded those skilled in the art.
Cellular telephones technologies communicate with a wireless network that is arranged as cells in a grid. Communication with the wireless network and the cellular telephone are established when the power to the cellular telephone is initially applied. The cellular telephone will attempt to locate the closest communication tower using criteria such as signal strength and triangulation techniques. Cellular telephones initially operate at a fixed frequency while communications are established with the network. The cellular telephone will attempt to locate the closest communication tower using criteria such as signal strength and triangulation techniques.